Jumpering fuel pump relay

Drew20

Well-Known Member
Site Donor
Messages
465
Reaction score
136
Location
Beaconsfield
just looking for an elusive fuel leak / weep in the engine bay, and I was hoping to run the fuel pump by jumpering at the fuel pump relay by the ECU. I don't have a wiring diagram so I'm checking in beforehand, just in case I do something bad to the ECU.... expensive!

Relay has 5 wires and 4 terminals:
85 and 86 connect to ECU, I assume are triggers for the relay
30/51 looks to be power, although it has no power (where is this powered from?)
87 has two wires, one goes to ECU and the other I think is power to the fuel pump

Might be easiest to run a fused 12v wire direct to the fuel pump power wire I guess, if 30/51 has no volts

Does anyone have a wiring diagram for a 72 CSi / CSL?
 

Wladek

Well-Known Member
Messages
1,305
Reaction score
792
Location
Gdansk, POLAND
Here you have diagrams
 

Attachments

  • 61pe5003CSI_EU_71.pdf
    1 MB · Views: 187
  • 61pe5005CSI_EU_73.pdf
    1.4 MB · Views: 155

Drew20

Well-Known Member
Site Donor
Messages
465
Reaction score
136
Location
Beaconsfield
Just checking in again, can you tell I'm paranoid about frying my ECU??

I measured resistance between the wire on the fuel pump relay term 87 and ground (wire disconnected of course) as 1.7ohms. So this should be the resistance across the fuel pump.

Per my maths this indicates the fuel pump takes about 8A, about 100 watts

This seems very high to me, anyone know what the draw on the fuel pump is supposed to be?

Then I'll quit faffing and just get on with it!!
 

Belgiumbarry

Well-Known Member
Messages
1,618
Reaction score
1,116
Location
Belgium
fuelpump is a electric motor ... so i think it draws more amps starting then once it is running ? 8A could be normal to get it started ?
 

Drew20

Well-Known Member
Site Donor
Messages
465
Reaction score
136
Location
Beaconsfield
Cool, thanks

Yes, I did some more reading and I think maybe resistance is not a great check here, as resistance will vary as the motor turns

Cheers
 

Drew20

Well-Known Member
Site Donor
Messages
465
Reaction score
136
Location
Beaconsfield
Cool, thanks

I found 3 fuel weeps, 2 of them on the cold start injector, and a 3rd on the pressure regulator

Couldn't see any leaks on the short injector lines. The view of the injector seals, where they fit in the manifold, is pretty poor with the runners in situ

Plus I've tackled the seals on the tank as well, so hopefully less likely to explode now:)
 
Top